Geared Fan Assembly Unified Case Design
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Solution Overview
Problem
Current gas turbine engines require separate oil bearing cavities for fan and high pressure shafts due to the presence of booster rotors, complicating the structural case design and increasing complexity.
Innovation Solution
A gearbox with two independent transmission paths allows the fan rotor to be coupled with one output gear and the booster rotor with another on the same side, sharing a single structural case and oil cavity, simplifying the engine design and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If booster rotors are placed between the fan reduction gearbox and the high pressure compressor, then the engine can achieve improved performance, but separate oil bearing cavities are required for the fan gearbox and high pressure shaft bearings, increasing structural complexity
Solution Approach 1:
The patent merges the fan drive system and high pressure compressor drive system into a single integrated gearbox structure. The gearbox housing contains both the fan reduction gears and high pressure shaft bearings within one unified structural case, eliminating the need for separate oil bearing cavities and reducing overall structural complexity while maintaining the performance benefits of having booster rotors.
Solution Approach 2:
The unified gearbox structure serves multiple functions: it provides reduction gearing for the fan, supports the high pressure shaft bearings, and houses both lubrication systems within a single structural case. This multi-functional design reduces the number of separate components and simplifies the overall engine architecture.
2Reliability
If two separate oil bearing cavities are used for fan gearbox and high pressure shaft bearings, then each component can be independently lubricated, but the structural case design becomes more complex
Solution Approach 1:
Within the unified gearbox housing, the patent segments the lubrication system into separate oil bearing cavities for the fan gearbox and high pressure shaft bearings. This allows independent lubrication paths and oil supply systems for each component while maintaining a single external structural case, thus achieving reliable independent lubrication without increasing external structural complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables a unified structural case for transferring loads and simplifies lubrication, reducing the number of oil bearing cavities and enhancing the engine's structural integrity and efficiency.
Implementation Method 1
a first portion having a first input gear coupled to a rotatable turbine shaft, a first output gear, and defining a first transmission path between the first input and output gears
Data Source
AI summary
An assembly for a gas turbine engine, with a gearbox including a first portion having a first input gear coupled to a rotatable turbine shaft, a first output gear, and defining a first transmission path between the first input and output gears, and a second portion having a second input gear coupled to the turbine shaft, a second output gear, and defining a second transmission path between the second input and output gears different from the first transmission path. A fan rotor is coupled to the first output gear and a booster rotor is coupled to the second output gear on a same side of the gearbox than the coupling between the fan rotor and the first output gear. A method of assembling a drive for a fan rotor and a booster rotor in a gas turbine engine is also disclosed.